Micro electro-mechanical systems (micromachines or MEMS devices) have a wide variety of applications and are becoming more prevalent in commercial products. MEMS devices are ideal for wireless devices because of their low power and loss along with high isolation and linearity characteristics operating in radio frequency (RF) ranges. In particular, MEMS devices are well suited for applications including cellular telephones, wireless networks, communication systems, and radar systems. In wireless devices, MEMS devices can be used as antenna switches, mode switches, transmit/receive switches, tunable filters, matching networks and the like.
One particular example of a structure used in MEMS devices is a tri-layer beam. Such a structure has been shown to provide reliable, repeatable performance in MEMS devices. Tri-layer beams are fabricated by any number of techniques with the fundamental idea being the formation of structure that has three functional layers, namely a second functional layer is deposited on a first and a third functional layer is deposited on the second. The first and third layers can be the same to create a high degree of geometric, mechanical, and thermomechanical symmetry.